Date: Mon, 15 Dec 1997 23:13:51 +1100 From: Bruce Evans <bde@zeta.org.au> To: merlin@ghostwheel.com, stable@FreeBSD.ORG Subject: Re: sysinstall/qcam problem with 2.2-stable Message-ID: <199712151213.XAA28082@godzilla.zeta.org.au>
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> Next... I commented out the lpt0 driver and added the following >for qcam0: > >#device lpt0 at isa? port? tty irq 7 vector lptintr >device qcam0 at isa? port "IO_LPT1" > > Everything SEEMED to be fine. Until I ran /stand/sysinstall, the >following error was displayed: > > Dec 15 00:28:28 amber /kernel: stray irq 7 This is probably correct behaviour. Using irq 7 in a driver breaks reporting of stray interrupts. > OK, I modified the qcam0 device to snag irq 7 in the same manner >that was used for the now disabled lpt0: > >device qcam0 at isa? port "IO_LPT1" tty irq 7 Don't do that. qcam doesn't use interrupts, and this line is missing a vector for the interrupt. The configuration error is not detected by config, and this line happens to be equivalent to: device qcam0 at isa? port "IO_LPT1" tty irq 7 vector 0 >Now, when I try to run sysinstall, the following is displayed as the >system crashes: > >Fatal trap 12: page fault while in kernel mode >fault virtual address = 0x0 >fault code = supervisor read, page not present >instruction pointer = 0x8:0x0 This is because the stray interrupt was sent to the "handler" at address 0 instead of the normal stray interrupt handler. Bruce
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